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[RFC,v2,37/47] hugetlb: remove huge_pte_lock and huge_pte_lockptr

Message ID 20221021163703.3218176-38-jthoughton@google.com (mailing list archive)
State New
Headers show
Series hugetlb: introduce HugeTLB high-granularity mapping | expand

Commit Message

James Houghton Oct. 21, 2022, 4:36 p.m. UTC 
They are replaced with hugetlb_pte_lock{,ptr}. All callers that haven't
already been replaced don't get called when using HGM, so we handle them
by populating hugetlb_ptes with the standard, hstate-sized huge PTEs.

Signed-off-by: James Houghton <jthoughton@google.com>
---
 include/linux/hugetlb.h | 28 +++-------------------------
 mm/hugetlb.c            | 15 ++++++++++-----
 2 files changed, 13 insertions(+), 30 deletions(-)

Comments

Peter Xu Nov. 16, 2022, 8:16 p.m. UTC | #1 
On Fri, Oct 21, 2022 at 04:36:53PM +0000, James Houghton wrote:
> They are replaced with hugetlb_pte_lock{,ptr}. All callers that haven't
> already been replaced don't get called when using HGM, so we handle them
> by populating hugetlb_ptes with the standard, hstate-sized huge PTEs.

I didn't yet check the rational at all, but just noticed there's one more
of it for ppc code:

*** arch/powerpc/mm/pgtable.c:
huge_ptep_set_access_flags[264] assert_spin_locked(huge_pte_lockptr(huge_page_shift(h),
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Patch

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 5378b98cc7b8..e6dc25b15403 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -1015,14 +1015,6 @@  static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
 	return modified_mask;
 }
 
-static inline spinlock_t *huge_pte_lockptr(unsigned int shift,
-					   struct mm_struct *mm, pte_t *pte)
-{
-	if (shift == PMD_SHIFT)
-		return pmd_lockptr(mm, (pmd_t *) pte);
-	return &mm->page_table_lock;
-}
-
 #ifndef hugepages_supported
 /*
  * Some platform decide whether they support huge pages at boot
@@ -1226,12 +1218,6 @@  static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
 	return 0;
 }
 
-static inline spinlock_t *huge_pte_lockptr(unsigned int shift,
-					   struct mm_struct *mm, pte_t *pte)
-{
-	return &mm->page_table_lock;
-}
-
 static inline void hugetlb_count_init(struct mm_struct *mm)
 {
 }
@@ -1307,16 +1293,6 @@  int hugetlb_collapse(struct mm_struct *mm, struct vm_area_struct *vma,
 }
 #endif
 
-static inline spinlock_t *huge_pte_lock(struct hstate *h,
-					struct mm_struct *mm, pte_t *pte)
-{
-	spinlock_t *ptl;
-
-	ptl = huge_pte_lockptr(huge_page_shift(h), mm, pte);
-	spin_lock(ptl);
-	return ptl;
-}
-
 static inline
 spinlock_t *hugetlb_pte_lockptr(struct mm_struct *mm, struct hugetlb_pte *hpte)
 {
@@ -1324,7 +1300,9 @@  spinlock_t *hugetlb_pte_lockptr(struct mm_struct *mm, struct hugetlb_pte *hpte)
 	BUG_ON(!hpte->ptep);
 	if (hpte->ptl)
 		return hpte->ptl;
-	return huge_pte_lockptr(hugetlb_pte_shift(hpte), mm, hpte->ptep);
+	if (hugetlb_pte_level(hpte) == HUGETLB_LEVEL_PMD)
+		return pmd_lockptr(mm, (pmd_t *) hpte->ptep);
+	return &mm->page_table_lock;
 }
 
 static inline
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d80db81a1fa5..9d4e41c41f78 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5164,9 +5164,8 @@  int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 				put_page(hpage);
 
 				/* Install the new huge page if src pte stable */
-				dst_ptl = huge_pte_lock(h, dst, dst_pte);
-				src_ptl = huge_pte_lockptr(huge_page_shift(h),
-							   src, src_pte);
+				dst_ptl = hugetlb_pte_lock(dst, &dst_hpte);
+				src_ptl = hugetlb_pte_lockptr(src, &src_hpte);
 				spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
 				entry = huge_ptep_get(src_pte);
 				if (!pte_same(src_pte_old, entry)) {
@@ -7465,6 +7464,7 @@  pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
 	pte_t *spte = NULL;
 	pte_t *pte;
 	spinlock_t *ptl;
+	struct hugetlb_pte hpte;
 
 	i_mmap_lock_read(mapping);
 	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
@@ -7485,7 +7485,8 @@  pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (!spte)
 		goto out;
 
-	ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
+	hugetlb_pte_populate(&hpte, (pte_t *)pud, PUD_SHIFT, HUGETLB_LEVEL_PUD);
+	ptl = hugetlb_pte_lock(mm, &hpte);
 	if (pud_none(*pud)) {
 		pud_populate(mm, pud,
 				(pmd_t *)((unsigned long)spte & PAGE_MASK));
@@ -8179,6 +8180,7 @@  void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
 	unsigned long address, start, end;
 	spinlock_t *ptl;
 	pte_t *ptep;
+	struct hugetlb_pte hpte;
 
 	if (!(vma->vm_flags & VM_MAYSHARE))
 		return;
@@ -8203,7 +8205,10 @@  void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
 		ptep = huge_pte_offset(mm, address, sz);
 		if (!ptep)
 			continue;
-		ptl = huge_pte_lock(h, mm, ptep);
+
+		hugetlb_pte_populate(&hpte, ptep, huge_page_shift(h),
+				hpage_size_to_level(sz));
+		ptl = hugetlb_pte_lock(mm, &hpte);
 		huge_pmd_unshare(mm, vma, address, ptep);
 		spin_unlock(ptl);
 	}